1. Field of the Invention
This invention relates to a method for automatically generating a simulation model from previously created structured analysis tools, and more particularly, to a method for automatically generating simulation models from previously created data flow diagrams and utilizing this simulation model as a tool for the design, integration and testing of the particular system being implemented by replacing components of the simulation model with the actual hardware/software components in short incremental steps. The simulation model can be created using any of the standard simulation languages on a plurality of host computers.
2. Discussion of the Prior Art
The fields of structured analysis and simulation modeling are an increasingly important technology due to the ever increasing complexity of systems to be designed. The purpose of both structured analysis and simulation is to design a realistic and accurate model of the particular system to be designed. The design of a realistic and accurate system is accomplished by performing an allocation of system functions. Structured analysis performs an allocation of system functions in order to implement the system, and simulation models perform an allocation of system functions in order to execute and analyze a model of the system. Basically, in the design of any multifaceted system, the use of structured analysis and simulation is indispensable regardless of how simplistic the system may appear to be. The concept behind these procedures is to first break the problem or system design requirements into smaller and more manageable parts, find a solution for each part, and then rebuild the parts into a complete and functioning system.
Analysis is the study of a problem prior to taking action to solve the problem. Structured analysis is a particular form of analysis which uses a set of standardized tools to partition the problem into smaller parcels such that they become more manageable. The primary tools of structured analysis are data flow diagrams, data dictionaries, and mini-specifications. Structured diagramming techniques support a top-down, structured development approach to problem solving with various levels of decomposition and thus various levels of detail for the particular system can be achieved. Early structured analysis tools were largely long hand procedures utilizing pencil and paper techniques. However, with the advent of widely available, multipurpose graphics terminals, structured analysis diagramming has become a quick and efficient automated process. A variety of vendors, including Cadre and Tektronix, have easy to use, commercially available structured analysis programs. These automated tools provide an efficient means for creating and updating structured analysis outputs which are the first step in generating a finished product from the initial problem or design requirements.
Simulation and modelling are widely accepted techniques whereby prior to actually building or constructing the particular product, a simulation or model is constructed to see if the product functions as envisioned and whether or not it is a feasible design. Modelling is the older of the two techniques and involves actually building a prototype of the product. This prototype or model may or may not be a fully working model or even built to scale, but rather, it typically is used to be representative of the particular product. This model would be subjected to various tests in order to determine if the design was sound and feasible. As time progressed, and the use of computers was becoming more prevalent, software routines were written to simulate the workings of hardware and software components that comprised the particular product. Today, simulation is a design-aid tool that has been in existence for nearly thirty years and is a highly exact science. This breakthrough has had an incredible impact on designing techniques; namely, by being able to simulate the product on a computer, a model that in all probability would not function, would not have to be built. The product could be simulated on the computer, tested and have a majority of the bugs worked out before the prototype was built. Although simulation time is somewhat expensive and time consuming, it represents an improvement in having to continuously build prototypes to work out the problems encountered.
The design of a particular system starts with the basic system concepts, the general idea of what is to be designed and what is expected of the design. Once the system concepts are fairly well established, the design of the system follows two diverging paths; namely, the hardware development path and the software development path. Basically, the two paths are similar in concept, but differ in the actual implementation of the various stages along the paths. The software development path starts with the system software requirements analysis and proceeds through software requirements analysis, preliminary design, detailed design, coding unit and CSC integration testing, and ends with the computer software configuration item testing. The hardware development path starts with the system hardware requirements analysis and proceeds through hardware requirements analysis, preliminary design, detailed design, fabrication and ends with the hardware configuration item testing. The basic tool utilized to go from the system concepts stage to the configuration item testing stage is structured analysis. Once this phase is completed, the next step would be to use system modelling through simulation to test the system, and finally to build, fabricate or code the finished product, namely, the completed and functional system. Currently, the use of structured analysis and system modelling have been separate and distinct steps in the design process, one to be used after the desired result is achieved with the other.